I've been trying to fix why my shadows look like this. Any help would be appreciated. I'm using Cycles and my GPU.
Are you referring to the "shadow" in the little brown table or the table on the top left? If it's the little brown table with the lamp on it, that might not be a shadow. That feels more like something with the shader or a texture maybe? Try making a render without anything around it, maybe even with the little table to see if those black sploshes remain.
That looks like artifacts from denoising to me. You're going to want to increase your render samples. Looks like right now there is still too much noise when the denoiser kicks in and it can't quite handle it.